Recovery of hydrogen halide



lug them.

,cmori crother halide.

Patented Apr. 2, l.

Boson e v v ration of Dole A lication I 33; 1943 Nc..i92.2

e on (on. zr-iss) The present invention is directed to the recovery of hydrogen halide irom gases contain- It has already been proposed to subject oases :1 vvith a hydrocarbon liquid carrying in on .9. salt cepeble of forming on edditioh compound with hydrogen halide. An anhyin copper salt, such as copper sulfate, is comprevlously lrnowu methods; oi contacting the s with olry copper sulfate or similur suit,

or with inert bodies carrying such salts.

There ere certeih disadvantages, however, otto tending the hydrocarbon suspension method, as heretofore practiced. One of these is the loot thethecouse these salts are crystulline in structure cud their surface only isefiective in the desired oction, the recovery of hydrogen halide per so high rates oi how in order to maintain the dcht sireel suspension.

: Accorp to the present invention, the More; seic'i hydrocarbon suspension method for hydrogen. hellcie recovery is improved by using the LII" on the sur- 30 motel suit in the form of "a. thin. 1' i'uce oi flue cley or ciiotomeceous earth or other porous materiel having slow specific prsvity cool e hioh ratio oi surface to volume. The motel suit may he deposited on the carrier by any of the methods commonly known in the art for the o5 preporetion oi supported cutulysts. For example. the city or other finely divided. material may be to ed in a. solution oi the salt and them illtered end cried. As a. perticulsr example, cli-' ed with o copper suliote by piecing u weighed count oirliutomuceous earth in naphtha, udding copper suliete to the ture in the form of 8. water or alcohol solution, thoroughly oeiteting the ore, filtering out the solidi, anal drying. it i sit Soil-toil" h. to remove water of hydration. e coated carrier iethen usecllnou'spenslon in an inert solvent such us CCh or kerosene ior 9. gas mixture containing hydrogen solvents, perticuierly thoseoi t e poromnic type. may be employed. Relatively low-boiling paraffin hydrocarbons. such as hexane. heptane, and the like-ere particularly suited for this purpose.

In practice, the method at the present to ,=.-'v.:=.n. hydrogen halides to scrubbing or p mo used for this purpose. This mode of oplo orutlon ofiere substantial advantages over the Other hydrocarbon 60 tion is quite similar totho known method, in which the crystalline catalyst is employed. Whereas. however, the known method usually involved the employment or about 25 per cent by weight oi anhydrous-copper sulfate, based on the hydrocerbou solvent utilized in the absorption step, the present method involves only a. small fraction of this amount of copper salt, the hull: of the solid matter being made up of carrler. It is oclventeeeous to use on amount of corrier plus motel solt constituting from 5 per cent to 25 per cent by welsht oi the hydrocsr hon employed. The upper limit of the amount of solid is dictetecl by the viscosity which may be tolerated" in the resulting suspension. Generally. the suspension will contain from about 5 per cent to it per cent of the 130116. and usually the copper sulfate will constitute from 2 per centto it per cent by weight of the solid.

. The prt pc is carried out in two stages, an absorption stripe end sdesorption stage. The conditions in the absorption stage should embrace temperatures in the range of 60F. to 100 F. at atmospheric pressure. The absorption may be carried out et higher pressures, up to about 350 pounds per square inch or higher. Temperate in excess of 100 F. may be employed, pnrticulerly when the higher prewures ere moihtelnecl. In any case, of course, the tempereture should not be such as to cause vaporizotiou'oi the hydr'ocei-bou ebsorption medium.

In the clesorpticn store the pressure may very widely, tiepenrliny on the pressure of the inlet see to the ebsorptlon stage. The temperatures found most useful in the desorption stepe are those routine between 325 and 380 F. The

actual upper limitiis that dictated by the disso ciotion temperatures oithe components of the absorption mixture end the melting point of the utomoceous earth of 200-300 mesh may be coutto copper sulfate or equivalent salt. The isct that some of the solvent employed may vaporize st the desorption temperature, is immaterial, since it can easily be recovered from the evolved gases current to a downwardly descendin gmixture of for securing contact between the gas and the absorption medium may be resorted to.

While particular mention of clays has been made in the foregoing description, it will be understood that other solid carriers may. be'employed in the practice or the present invention. Particularly useful are the various types of activated carbon and coke, These materials, when finely ground, tend to form stable suspensions with oil. A particularly useful material in this capacity is expanded vermiculite 'or mica, which is extremely light and which, in finely divided form, will remain suspended in oil for a considerable period.

The nature and objects of the present invention having'been thus described, what is claimed as new and useful and is desired to be secured by Letters Patent is:

1. A process for recovering a hydrogen halide from admixture thereof with other gases which comprises contacting the hydrogen halide-containing gas with a suspension of an anhydrous metal salt having a high absorption capacity for the hydrogen halide, supported in the form of a thin film on a light carrier suspended in an anhydrous liquid of organic character inert to hydrogen halide, and then subjecting the said suspension containing an absorbed hydrogen halide to desorption conditions.

2. A process according to claim 1 in which the vmetal salt is copper sulfate and the anhydrous liquid is a paraflinic oil.

'7. A process according .to claim 1 in which the carrier is clay,

8. A process according to claim 1 in which the carrier is a finely divided carbonaceous material. 9. A process accordingto claim 1 in which the carrier is an expanded vermiculite.

ALBERT J. $HlViI[l)l.-.

which the 

